Segments

NSX-V included the concept of a VXLAN Network Identifier, or VNI. A VNI is the equivalent of a port group on a Distributed Virtual Switch (VDS) in VMware vSphere. However, it is located behind an NSX-V logical switch. VMware NSX-T Data Center uses GENEVE encapsulation instead of VXLAN, so the concept of a VNI is not relevant. Instead, VMware NSX-T Data Center uses a construct called an overlay backed segment.

VMware NSX-T Data Center also allows for VLAN backed segments, which are segments for which the traffic is not GENEVE encapsulated.

The VMware NSX-T Data Center for VxBlock System design uses segments for North-South and East-West traffic. The segments are used for uplinks to the ToR switches and overlay traffic for customer T1 gateway subnets. The N-VDS uses the overlay traffic segments to enable the hosts to pass the traffic through the overlay network.

  • The 9k-a-seg carries the north-south traffic to the Cisco Nexus 9000 Series ToR 9K-A switch.
  • The 9k-b-seg carries the north-south traffic to the Cisco Nexus 9000 Series ToR 9K-B switch.
  • The T1-seg-1 carries the T1 gateway east-west traffic flows on the overlay network.
  • The T1-seg-2 carries the T1 gateway east-west traffic flows on the overlay network.

The VMware NSX-T Data Center for VxBlock System design instantiates two segments on the T1 gateway. These segments enable testing of intersegment routing after the VMware NSX-T Data Center deployment is completed. If the segments are not needed, you can safely delete them.